Characterization of the surface chemistry of silicon nitride powders

• Introduction: Silicon nitride is a ceramic material with a potential for high strength at room as well as elevated temperatures, good thermal shock resistance and relatively good oxidation resistance. However, optimal properties can only be realized when the microstructure and the grain boundary composition of the sintered body is controlled. Several studies have shown that the surface properties of the starting powder, together with the choice and addition of sintering aids, play a decisive role in determining the final properties [1-3]. However, the final properties of the sintered material depend on many different parameters. These parameters include the green-body characteristics, the physical and bulk chemical powder properties and the sintering conditions together with the powder surface chemical properties. Hence, it has been difficult to define the relationship between only the surface chemical properties and materials properties more precisely. Also, it is not clear how the relevant surface properties of silicon nitride should be characterized and quantified. This paper is a part of a review on the surface chemistry of silicon nitride [4]. The focus will be on an overview of the methods that are available to characterize relevant surface properties of ceramic powders, together with a summary on the present understanding of the surface chemistry of silicon nitride.

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